JP2807462B2 - Liquid jet recording method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid jet recording method, and more particularly, to a color jet recording method in bubble jet type liquid jet recording.

2. Description of the Related Art Non-impact recording methods have recently attracted attention in that the generation of noise during recording is extremely small to a negligible level. Among them, the so-called ink jet recording method, which can perform high-speed recording and can perform recording on so-called plain paper without requiring a special fixing process, is an extremely powerful recording method. Some have been proposed and commercialized with improvements, while others are still being put to practical use.

In such an ink jet recording method, recording is performed by flying droplets of a recording liquid called so-called ink and attaching the droplets to a recording member. The control method for controlling the flying direction of the generated recording liquid droplet is roughly classified into several types.

First, the first system is, for example, a system disclosed in US Pat. No. 3,060,429 (Tele type system), in which droplets of a recording liquid are generated by electrostatic attraction, and the generated droplets of the recording liquid are converted according to a recording signal. The electric field is controlled, and recording is performed by selectively adhering the recording liquid droplets onto the recording member.

More specifically, in more detail, an electric field is applied between the nozzle and the accelerating electrode to discharge a uniformly charged droplet of the recording liquid from the nozzle, and the discharged droplet of the recording liquid is converted into a recording signal. In accordance with this, recording is performed by causing the droplets to fly between the xy deflection electrodes configured so as to be electrically controllable and selectively adhering small droplets onto the recording member by a change in the intensity of the electric field.

The second method is a method (Sweet method) disclosed in, for example, US Pat. No. 3,596,275, US Pat. No. 3,298,030, in which a droplet of a recording liquid whose charge amount is controlled by a continuous vibration generation method is generated, and the generated charging is performed. The recording is performed on the recording member by flying a controlled amount of droplets between the deflection electrodes to which a uniform electric field is applied.

More specifically, a charging electrode configured so that a recording signal is applied in front of an orifice (ejection port) of a nozzle, which is a part of a recording head provided with a piezoelectric vibrating element, is separated by a predetermined distance. The piezoelectric vibrating element is mechanically vibrated by applying an electric signal of a constant frequency to the piezoelectric vibrating element, and a droplet of the recording liquid is discharged from the discharge port. At this time, a charge is electrostatically induced in the recording liquid droplet discharged by the charging electrode, and the droplet is charged with a charge amount according to the recording signal. When the droplet of the recording liquid whose charge amount is controlled flies between the deflection electrodes to which a constant electric field is uniformly applied, the droplet is deflected according to the added charge amount and carries a recording signal. Only the recording material can be deposited on the recording member.

The third method is a method (Hertz method) disclosed in, for example, US Pat. No. 3,416,153, in which an electric field is applied between a nozzle and a ring-shaped charging electrode to generate and atomize small droplets of a recording liquid by a continuous vibration generation method. This is the method of recording. That is, in this method, the atomization state of the small droplet is controlled by modulating the electric field intensity applied between the nozzle and the charging electrode in accordance with the recording signal, and the image is recorded with the gradation of the recorded image.

The fourth method is, for example, a method (Stemme method) disclosed in US Pat. No. 3,747,120, which is fundamentally different from the above three methods in principle.

That is, in each of the three methods, the droplet of the recording liquid discharged from the nozzle is electrically controlled during the flight, and the droplet carrying the recording signal is selectively attached to the recording member. On the other hand, according to the Stemme method, recording is performed by ejecting a small droplet of recording liquid from an ejection port in accordance with a recording signal.

That is, in the Stemme method, the piezoelectric vibrating element attached to the recording head having the ejection port for ejecting the recording liquid includes:
Applying an electrical recording signal, converting the electrical recording signal into mechanical vibration of a piezo-vibrating element, and ejecting a droplet of the recording liquid from the ejection port in accordance with the mechanical vibration to cause the droplet to fly and adhere to the recording member. Is to record.

Each of these four conventional methods has its own features, but on the other hand, there are points that can be solved.

That is, in the first to third methods, the direct energy of the generation of the droplet of the recording liquid is electric energy,
Droplet deflection control is also electric field control. Therefore, the first method is simple in structure, but requires a high voltage to generate small droplets, and is not suitable for high-speed printing because it is difficult to use a multi-nozzle recording head.

The second method is capable of multi-nozzle recording heads and is suitable for high-speed recording. However, a plurality of recording heads are difficult to electrically control recording liquid droplets, and satellite dots are formed on recording members. Are liable to occur.

The third method has a feature that an image having excellent gradation can be recorded by atomizing a recording liquid droplet, but on the other hand, it is difficult to control the atomization state, and fogging occurs in the recorded image. That the multi-nozzle of the recording head is difficult,
There are problems such as being unsuitable for high-speed recording.

The fourth scheme has relatively many advantages over the first to third schemes. That is, in order to perform recording by discharging the recording liquid from the discharge port of the nozzle on demand (on-demand), it is simple in terms of the configuration. Medium, small droplets not required for image recording can be collected and are unnecessary, and the first and second
As in the method (1), there is no need to use a conductive recording liquid, and there is a great advantage that the recording liquid has a large degree of freedom in terms of material. However, on the other hand, it is difficult to form a multi-nozzle recording head because there are problems in processing the recording head and it is extremely difficult to reduce the size of the piezoelectric vibrating element having a desired resonance number. However, since the recording liquid droplets are ejected and fly by the mechanical energy of mechanical vibration of the piezo-vibration element, it is not suitable for high-speed recording.

Furthermore, Japanese Patent Application Laid-Open No. 48-9622 (corresponding to US Pat. No. 3,747,120) describes, as a modification, the use of thermal energy instead of the use of mechanical vibration energy by means such as the above-described piezo-vibration element. Have been.

That is, the above-mentioned publication describes that a heating coil that directly heats a liquid in order to generate a vapor that causes a pressure increase is used as a pressure increasing means instead of the piezoelectric vibrating element.

However, the above publication discloses that a heating coil serving as a pressure increasing means is energized to directly evaporate the liquid ink in a bag-shaped ink chamber (liquid chamber) having only one opening through which the liquid ink can enter and exit. However, there is no suggestion as to how to heat the liquid when the liquid is continuously and repeatedly discharged. In addition, since the position where the heating coil is provided is provided at the deepest part of the bag-shaped liquid chamber far from the supply path of the liquid ink, in addition to being complicated in terms of the head structure, continuous It is not suitable for repeated use.

Moreover, according to the technical contents described in the above-mentioned publication, it is not possible to quickly form a preparation state for the next liquid discharge after performing the liquid discharge with the generated heat which is practically important.

As described above, the conventional method has advantages and disadvantages in terms of configuration, high-speed recording, multi-nozzle recording head, generation of satellite dots and occurrence of fogging of a recorded image, etc. There was a restriction that only the application was possible.

Japanese Patent Application Laid-Open No. 57-12658 discloses a plurality of orifices juxtaposed on an ink ejection surface for ejecting inks of two or more different colors as droplets, and a plurality of orifices provided for each color of ink. A common ink chamber, a number of liquid chambers each having an orifice connected to a common ink chamber corresponding to the color of ink to be ejected, and energy for ejection corresponding to an image signal is generated in the liquid chamber. In an apparatus for performing color ink-jet recording by a head having an energy generating means for causing energy to be generated, it has been proposed to generate energy in accordance with each color ink, as described in JP-A-57-12658. Is merely an ambiguous expression of "generation of energy in accordance with ink", and lacks specificity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in particular, uses a plurality of bubble jet type liquid jet recording heads, and makes the ejection performance of each color ink uniform when the recording head is used for color recording. It is done for the purpose of.

In order to achieve the above-mentioned object, a flow containing a recording liquid to be introduced, and a heat energy acting portion for generating a bubble in the recording liquid by heat and generating an action force accompanying an increase in the volume of the bubble are provided. A passage, an orifice communicating with the flow path to discharge the recording liquid as droplets by the action force, and a liquid chamber communicating with the flow path and introducing the recording liquid into the flow path. A liquid ejecting recording head using a liquid ejecting recording head comprising means for introducing the recording liquid into the liquid chamber, wherein a plurality of liquid ejecting recording heads ejecting recording liquids of a plurality of colors or densities are used; Among the recording liquids of the plurality of colors or densities, (1) the liquid jet recording head that uses a recording liquid having a viscosity higher than that of the other recording liquids is a drive applied to the thermal energy action section. Wherein the thermal energy for the recording is higher than the thermal energy of the liquid jet recording head using a recording liquid having a low viscosity of the recording liquid, or (2) the surface tension is higher than that of another recording liquid. In the liquid jet recording head using a large recording liquid, the thermal energy for driving applied to the thermal energy action section is higher than the thermal energy of the liquid jet recording head using a recording liquid having a small surface tension of the recording liquid. It is characterized by. Hereinafter, a description will be given based on an example of the present invention.

The present invention has been made to solve the drawbacks of the invention described in the above-mentioned Japanese Patent Application Laid-Open No. 57-12658. In particular, a plurality of types of recording liquid (ink The present invention relates to a method of driving a recording head in the case of using ()).

1 (a) and 1 (b) are configuration diagrams for explaining an embodiment of the present invention, respectively, and FIG. 2 is an operation description of a valve jet head as an example of an ink jet head to which the present invention is applied. FIG. 3 is a perspective view showing an example of a bubble jet head, and FIG. 4 is a lid substrate (FIG. 4 (a)) and a heating element substrate (FIG. 4A) constituting the head shown in FIG. FIG. 4 (b)) is an exploded perspective view, FIG. 5 is a perspective view of the lid substrate shown in FIG. 4 (a) viewed from the back side, in which 11 is a lid substrate, and 12 is a lid substrate. Heating element substrate, 13 is a recording liquid inlet, 14 is an orifice, 15 is a flow path, 16 is a region for forming a liquid chamber, 17 is an individual (independent) electrode, 18 is a common electrode,
19 is a heating element (heater), 20 is a recording liquid (ink), 21 is a bubble, and 22 is a flying ink droplet. The present invention is applied to such a bubble jet type liquid jet recording head.

First, the ink ejection by the bubble jet will be described with reference to FIG. 2. (a) is a steady state, and the surface tension of the ink 20 and the external pressure are in an equilibrium state at the orifice surface.

6B shows a state in which the heater 19 is heated until the surface temperature of the heater 19 rises rapidly and a boiling phenomenon occurs in the adjacent ink layer, and minute bubbles 21 are scattered.

(C) is a state in which the adjacent ink layer heated rapidly on the entire surface of the heater 19 is instantaneously vaporized to form a boiling film, and the bubbles 21 grow. At this time, the pressure in the nozzle rises by an amount corresponding to the growth of the bubble, the balance with the external pressure on the orifice surface is lost, and the ink column starts to grow from the orifice.

(D) is a state in which the bubble has grown to the maximum, and the ink 20 corresponding to the volume of the bubble is pushed out from the orifice surface. At this time, no current is flowing through the heater 19, and the surface temperature of the heater 19 is decreasing. The maximum value of the volume of the bubble 21 is slightly delayed from the timing of applying the electric pulse.

(E) shows a state where the bubble 21 is cooled by the ink or the like and starts to contract. At the front end of the ink column, the ink moves forward while maintaining the pushed speed, and at the rear end, the ink flows backward from the orifice surface into the nozzle due to a decrease in the nozzle internal pressure due to the contraction of the bubble, and the ink column is constricted. .

4F, the bubble 21 is further contracted, the ink comes into contact with the heater surface, and the heater surface is cooled more rapidly. At the orifice surface, the external pressure is higher than the internal pressure of the nozzle, so that the meniscus largely enters the nozzle. The tip of the ink column becomes a droplet and moves in the direction of the recording paper.
Flying at a speed of 10m / sec.

(G) is a process in which the ink is again supplied (refilled) to the orifice by capillary development and returns to the state of (e).
The bubbles have completely disappeared.

In the embodiment shown in FIG. 1A, the recording head shown in FIG. 2 uses four colors of Y (yellow), M (magenta), C (cyan), and B (black) for the respective colors. FIG. 4 is a plan view of a color head module arranged in a line for each color. Generally, in the color ink jet technology, an effort is made to make the physical properties (especially, viscosity and surface tension) of recording liquids (inks) of a plurality of colors equal. However, it is difficult to make the physical property values equal for all the colors because intrinsically different dyes are used. If the physical property values are different, completely different ejection performance is shown for each color. For example, when the ink viscosities are different, when the viscosity is high, bubbles are less likely to be generated, and the ejection is more difficult than the orifice. The same can be said for the surface tension of the ink. If the surface tension is large, a large force is required when the ink is ejected from the orifice, and it becomes difficult to eject the ink.

The present invention has been made in view of the above points, and (a). When using ink with high viscosity, the energy (pulse voltage, pulse width,
Current, etc.) is made higher than when low viscosity ink is used, bubbles are easily generated, and the ink is more easily ejected than the orifice.

(B). When ink having a large surface tension is used, the energy applied to the thermal energy action section is made higher than when using ink having a small surface tension, so that the ink can be more easily ejected than the orifice.

It is like that.

FIG. 1 (b) is a plan view of a head module in which three heads (I, II, and III) of FIG. 2 are used, and ink of which density is changed in a single color is used. As in the case where the color is changed, the physical properties of the ink are changed even when the density of the ink is changed. Therefore, in this case, the present invention described in the above (a) and (b) is applied. Although FIGS. 1A and 1B are separately shown in FIG. 1, it goes without saying that the present invention is also applied to a head module having different colors and densities.
Further, in the above, the bubble jet using the heating element has been described.
The invention can also be applied to a bubble jet using a pulse laser or using discharge energy.

FIG. 6 is a view for explaining another means for generating bubbles in the recording liquid. In the figure, 31 is a laser oscillator, 32 is an optical modulation drive circuit, 33 is an optical modulator, 34 is a scanner, 35 Is a condenser lens, and the laser light generated by the laser oscillator 31 is pulse-modulated in the optical modulator 33 in accordance with an image information signal which is input to the optical modulator driving circuit 32, is electrically processed, and is output. . The pulse-modulated laser light passes through a scanner 34 and is condensed by a condenser lens 35 so as to be focused on the outer wall of the thermal energy action section. To generate air bubbles. Alternatively, the wall 36 of the thermal energy action section is made of a material that is permeable to laser light, and is focused by the condenser lens 35 so that the recording liquid 37 inside is focused, and the recording liquid is directly heated. May generate bubbles.

FIG. 7 is a view for explaining an example of a printer using the laser light as described above. The nozzle section 41 has a high density (for example, 8 nozzles / mm) and a paper width (for example, A
4 width) shows an example in which the components are integrated so as to cover the entirety.

The laser light emitted from the laser oscillator 31 is applied to an optical modulator.
Guided to 33 entrance openings. In the optical modulator 33, the laser light is subjected to strong and weak modulation according to an image information input signal to the optical modulator 33. The optical path of the modulated laser light is bent by the reflector 38 in the direction of the beam expander 39, and enters the beam expander 39. The beam diameter is expanded by the beam expander 39 while keeping the parallel light.
Next, the laser beam having the expanded beam diameter is incident on a rotating polygon mirror 40 that rotates at a high speed and a constant speed. The laser light swept by the rotating polygon mirror 40 forms an image on the outer wall 36 of the thermal energy action section of the drop generator or on the recording liquid inside by the condenser lens 35. As a result, air bubbles are generated in each of the thermal energy action sections, and the recording liquid droplets are ejected to perform recording on the recording paper 32.

FIG. 8 is a view showing still another bubble generating means. In this example, a pair of discharge electrodes 50 arranged on the inner wall side of the thermal energy action section receives a high voltage pulse from a discharge device 51,
A discharge is generated in the recording liquid, and bubbles are instantaneously formed by heat generated by the discharge.

9 to 16 are diagrams showing specific examples of the discharge electrode shown in FIG. 8, respectively. In the example shown in FIG. Discharge (at low energy).

In the example shown in FIG. 10, two flat electrodes are used so that air bubbles are stably generated between the electrodes. The position of the generated bubble is more stable than the needle-shaped electrode.

In the example shown in FIG. 11, a substantially coaxial hole is formed in the electrode. Both holes of the two electrodes serve as guides, and the position of the generated bubbles is further stabilized.

The example shown in FIG. 12 is a ring-shaped electrode, and is basically the same as the example shown in FIG. 11, and is a modified embodiment thereof.

In the example shown in FIG. 13, one is a ring-shaped electrode and the other is a needle-shaped electrode. The ring-shaped electrode aims at stability of generated bubbles, and the needle-shaped electrode aims at efficiency by concentrating an electric field.

In the example shown in FIG. 14, one ring-shaped electrode is formed on the wall surface of the thermal energy action section. This aims at facilitating the production of forming electrodes in a plane on the substrate, in addition to the effect of the example shown in FIG. A plurality of such planar electrodes having high density can be easily manufactured by vapor deposition (or sputtering) or photo-etching technology. Especially effective for multi-array.

In the example shown in FIG. 15, the ring-shaped electrode forming portion of the example shown in FIG. 14 is formed along the outer periphery of the electrode and is raised one step from the periphery. Again, the stability of the generated bubbles is aimed at, and it is more stable than that shown in FIG. 13 by adding a three-dimensional guide.

The example shown in FIG. 16 is different from the example shown in FIG. 15 in that the ring-shaped electrode forming portion has a structure in which the ring-shaped electrode is dropped from the periphery, and again, the generated bubbles are formed stably. Is done.

Effects As is apparent from the above description, according to the present invention, the ejection performance of the bubble jet type liquid jet head using different inks (colors and densities) can be made uniform, and high image quality can be obtained.

[Brief description of the drawings]

1 (a) and 1 (b) are each a main part configuration diagram for explaining an embodiment of the present invention, and FIG. 2 is an operation of a bubble jet head as an example of an ink jet head to which the present invention is applied. FIG. 3 is a perspective view showing an example of a bubble jet head, FIG. 4 is an exploded perspective view, FIG. 5 is a view of a lid substrate viewed from the back side, and FIG. FIG. 7 is a diagram illustrating an example of a bubble generating unit using laser light, FIG. 7 is a diagram illustrating an example of a printer,
FIG. 8 is a diagram for explaining an example of a bubble generating means using discharge, and FIGS. 9 to 16 are diagrams showing specific examples of the discharge electrode shown in FIG. 8, respectively. Y, M, C, B, I, II, III …… Recording head, 11… Cover substrate, 12…
... heating element substrate, 17, 18 ... electrodes, 19 ... heating element, 20 ...
Ink, 21 ... bubbles, 22 ... flying ink droplets.

Claims (2)

(57) [Claims] 1. A storage device for accommodating a recording liquid to be introduced,
A flow path provided with a thermal energy action portion for generating bubbles in the recording liquid by heat and generating an action force in accordance with an increase in the volume of the bubbles; and connecting the recording liquid by the action force to communicate with the flow path. An orifice for discharging droplets, a liquid chamber for communicating with the flow path and introducing the recording liquid into the flow path, and a liquid jet recording head comprising means for introducing the recording liquid into the liquid chamber. A liquid ejection recording method to be used, wherein a plurality of liquid ejection recording heads ejecting recording liquids of a plurality of colors or densities are used, and among the recording liquids of the plurality of colors or densities, another recording liquid having a viscosity The liquid jet recording head using a higher recording liquid has a thermal energy for driving applied to a thermal energy action section of the liquid jet recording head using a recording liquid having a low viscosity of the recording liquid. Liquid jet recording method characterized by higher than the thermal energy of the recording head. 2. A storage device for accommodating a recording liquid to be introduced,
A flow path provided with a thermal energy action section for generating air bubbles in the recording liquid by heat and generating an action force in accordance with an increase in the volume of the air bubbles; And an orifice for discharging the liquid, a liquid chamber for communicating with the flow path and introducing the recording liquid into the flow path, and a liquid ejecting recording head including means for introducing the recording liquid into the liquid chamber. A liquid ejecting recording method, comprising using a plurality of liquid ejecting recording heads for ejecting a plurality of types of colors or densities of recording liquids, wherein a surface tension of another of the plurality of types of colors or densities of recording liquid is other In the liquid jet recording head using a larger recording liquid, the thermal energy for driving applied to the thermal energy action section is reduced before using the recording liquid having a small surface tension of the recording liquid. Liquid jet recording method characterized by higher than the thermal energy of the liquid jet recording head.